1. Parathyroid hormone measurement in CKD
Jean-Claude P. Souberbielle, Hubert Roth, Denis P. Fouque 
Kidney International 
Volume 77, Issue 2, Pages (January 2010)
DOI: /ki
Copyright © 2010 International Society of Nephrology Terms and Conditions

2. Figure 1
Amino-acid sequences. 1–84 PTH (a), 7–84 PTH (b), and N-PTH (c). Both second- and third-generation PTH assays use two antibodies directed toward different epitopes. In both generations of assays, the capture antibody (coated to a solid phase) is directed toward the 39–84 portion of the PTH molecule. In the Ca-PTH (third generation) assay, the labeled antibody recognizes the 1–4 portion and, thus, may bind to both 1–84 PTH and N-PTH, but not to the 7–84 PTH (as the 1–4 amino acids of the 1–84 PTH are absent). In most second-generation assays, the labeled antibody is directed toward the 15–20 portion of the 1–84 PTH molecule and, thus, may bind to both 1–84 PTH and 7–84 PTH, but not to the N-PTH (as, probably, the Ser17 of the 1–84 PTH is phosphorylated, which prevents binding of the labeled antibody). In some second-generation assays (such as the Roche assay), the labeled antibody is directed toward the 26–32 portion of the 1–84 PTH molecule and, thus, may bind to 1–84 PTH, 7–84 PTH, and N-PTH.
Kidney International  , DOI: ( /ki )
Copyright © 2010 International Society of Nephrology Terms and Conditions